Dirtier runoff likely with unusually heavy snowfall, rain

On a bridge behind a strip mall on Liberty Road just west of Baltimore, a group of state biologists trekked out in the morning drizzle Monday to gauge the health of the Chesapeake Bay.

From the bridge over the Gwynns Falls, they lowered a device about 2 feet into the brown-green water to take the temperature and measure the dissolved oxygen. Then they lowered a bottle with a small crane to collect a water sample, checking for sediment, nutrients and solids.

The effort, made at 54 sites each month across the state since 1986, shows the short- and long-term health of Maryland's streams, the Inner Harbor and, ultimately, the Chesapeake Bay. The results not only help guide those who regulate pollution, but help the biologists show how the way people live and work affects the water quality nearby and downstream.

Monday's tests came on the heels of record snow and above-average rain that likely washed extra pollutants into the water. This could signify an early onset of dead zones, the oxygen-deprived stretches in the bay where underwater grasses can't grow and fish can't live.

In about 85 percent of the state's nontidal streams, including the Gwynns Falls, the conditions are improving largely because of upgrades to wastewater treatment plants across Maryland in recent years, said Thomas A. Parham, director of tidewater ecosystem assessment at the state Department of Natural Resources.

But increases in development and population have meant more suburban and urban storm water runoff. And agricultural runoff, while not increasing, remains the biggest polluter, he said. Big snow and rain events always bump up the amount of pollution, even if it's just temporary.

"We still have a long way to go," Parham said. "People need to know the actions they take affect the bay. If we want a bay we can fish and swim in, we need to continue taking steps."

Parham said he would not fish or swim in this stretch of the Gwynns Falls.

All of the extra pollution, particularly the nutrients nitrogen and phosphorus, provides food for algae. The resulting algae blooms eventually die, decompose and use up the oxygen in the water. And in the bay, where water flushes slowly, dead zones form.

There are steps in the works to further reduce runoff. Federal regulators are considering new rules for farmers to control pollution. And the Assembly passed but is reconsidering new rules for developers to mitigate storm water runoff.